1. Field of the Invention
The invention concerns an electronics device for a magnetic resonance apparatus, of the type having a housing in which one or more electronic components to be cooled are accommodated.
2. Description of the Prior Art
For cost reasons, electronic components inside the RF shielding cabinet of magnetic resonance apparatuses are subject to an ever greater bundling into compact electronic devices or electronic units. Since a large portion of the contained functions pertain to the area in close proximity to the magnet, it is recommended to install these electronic devices directly in this region. For a compact design, an electronic device has a housing in which the required electronic components are arranged (frequently in modular configuration).
Because a power loss inevitably accumulates in the operation of the magnetic resonance apparatus or the electronics unit, a portion of which is emitted to the ambient atmosphere and consequently leads to heating, it is necessary to dissipate the accumulated heat. A pure convection cooling of the electronics device cooling or of the components contained therein serves for this purpose. The electronics device is typically arranged between the magnet and a casing wall. A number of ventilation slits that enable an air entrance in the region between the casing and the magnet are provided at the lower end of the casing for the convective cooling. The housing of the electronics device also has air entrance and exit openings so that an air flow can be drawn through the electronic device. The heated air escapes at the upper end, meaning that an air channel must be provided within the entire region from the lower air entrance in the region behind the casing up to the upper air exits. This inevitably also entails problems with regard to possible contamination because dust and other particles contained in the air can be drawn into the region between the magnet and the casing (as well as into the electronics device itself, naturally). Problems with water condensation can also occur in the housing during the refilling of the coolant cooling the superconducting magnet or upon a quench of the magnet.